A lot of bad drivers here.
Anyone who says you need 100% concentration on the road ahead is talking out of their arse.
Peripheral vision is highly valuable (with racing/rally driving you practically never look at whats directly in front of you unless you want to crash). Rear-view and wing mirrors are indispensable and a requirement to pass your test. Checking your speed, engine temps, dash information - all essential to driving.
So; to say a pair of glasses that can provide a graphical HUD to display this information in one place WILL cause you to crash is utter bollocks.
Obviously they would need to implement some way of preventing the user from reading their emails/text. But IMO, those users who want to read their emails while driving will just go straight for their mobile phone and do it anyway! So whats the point?
Why penalise those of us who would like to see practical uses applied to this technology to spite those that would flaunt this privilege?